Letters to the Editors, January/February 2010

SOCIAL EXHAUSTIONIn “The Social Cure,” Jolanda Jetten, Catherine Haslam, S. Alexander Haslam and Nyla R. Branscombe state: “Membership in lots of groups—at home, work, the gym—makes us healthier and more resilient.” But we are not all the same. For extroverts that formula makes sense, but for introverts it does not. Unlike extroverts, who are energized by social mingling, introverts typically find the experience at the least uncomfortable and, more often than not, downright exhausting.

COGNITION IN THE WOMBAs a published freelance researcher specializing in prematurity, I must point out that Christof Koch in “When Does Consciousness Arise?” [Consciousness Redux] really short-changes the fetus. Learning, memory and language begin in utero. Psychologically, the fetus starts learning with the occurrence of the first reflexes. Reflexes are the road to exploration and discovery—predominantly about the self—and to learning new behaviors. The first type of learning to emerge is habituation, when the fetus shows a decreasing response to a stimulus each time it appears. A few babies show habituation as early as 23 weeks of gestation, and by 29 weeks all healthy fetuses can do it. Habituation shows that memory and cognition are developing.

In one recent example, a Dutch team led by Jan Nijhuis established that fetuses as young as 30 weeks’ gestational age responded with a startle to a specific stimulus, in this case, a “vibroacoustic stimulation.” After repeated stimuli, the fetuses stopped responding, meaning the stimulus had become a “safe” one—that is, the fetuses habituated. That study is one of many that offer evidence for fetal learning and memory.

Paula M. S. Ingalls
Bernard, Maine

PAIN AND HORMONESAs a physical therapist, I found “I Do Not Feel Your Pain,” by Ingrid Wickelgren, extremely interesting, but I question the part of the article that discusses female hormone levels and the effect they have on pain perception. I find that women (myself included) have more pain toward the end of their menstrual cycle when estrogen is lower, not when estrogen is higher as the article suggests. I have also experienced more pain while taking birth-control pills. Perhaps there is another chemical phenomenon at work.

KNOW MUCH ANTHROPOLOGY?Wray Herbert’s article “Don’t Know Much Biology” [We’re Only Human] exaggerates the human problem with learning biology because he relies on studies of modern urban Americans who have essentially no interaction with nature. All of us anthropologists who study traditional rural cultures are struck by the incredible knowledge of biology that even very young children have. They not only recognize hundreds of species of plants and animals, but they also know which varieties are related to which others, what is alive and what is not, and so on—the very things that the American students in the studies Herbert cites do not know. Recent studies of this effect in traditional cultures by anthropologist Norbert Ross of Vanderbilt University and psychologist Douglas Medin of Northwestern University confirm it rigorously.